This invention relates to a dynamically tuned gyro. More particularly, it relates to a dynamically tuned gyro in which a rotary shaft of a spin motor and a rotor are combined into one unit to reduce the number of component parts and to simplify the structure and in which the device in its entirety is in the form of an axially elongated column to provide for a more stabilized gyro operation.
Various constructions of the dynamically tuned gyro are known in the art, as typified by the construction shown in FIG. 3 of the Japanese Patent Publication KOKAI No. 60-237313. Another proposal for the construction of a dynamically tuned gyro is shown in FIG. 4 of my Japanese laid open application No. 62-162618 published Oct. 16, 1987 and is shown in FIG. 1 of this application.
Referring to FIG. 1, the numeral 1 designates a casing having a cross section in the shape of an inverted letter U. A frame member 3, having a pair of ball bearings 2, is mounted by a press fit on an inner wall 1a of the casing 1.
A stator 4a having a stator winding 4 is fixedly mounted to an inner wall 3a of the frame member 3. A rotor shaft 5 is secured for rotation to an inner ring 2a of each of the bearings 2.
The frame member 3 is secured to an outer ring 2b of each of the bearings 2. An annular hysteresis ring 7 is secured to the outer periphery of an end cap 6 which is secured to the lower end 5b of the rotor shaft 5 and to the inner bearing rings 2a, and which as a whole is cup-shape. The end cap 6 and the hysteresis ring 7 make up a motor rotor 8, while the stator 4a and the motor rotor 8 make up a spin motor 9.
A gyro rotor 13 is secured to the upper portion of the rotor shaft 5 by means of a hinge unit 12 formed by a gimbal 10 and a spring member 11. This gyro rotor 13 is constituted by a ring-shaped member having a cross section substantially in the form of a letter U, while a ring magnet 14 is secured to the inner wall of the gyro rotor 13.
A disk-shaped stop 21 is secured to the upper end of the rotor shaft 5 in such a manner that the gyro rotor 13 will abut on the periphery of the stop 21 when the gyro rotor is in an inclined position.
A sensor ring 15 is secured to the lower end of the gyro rotor 13, while a sensor coil 16 is mounted upright on the frame member 3, facing the sensor ring 15.
A torquer coil 17 is mounted on the upper surface of the frame member 3. The torquer coil 17 is mounted upright so that the foremost part of the torquer coil is disposed within the space of the gyro rotor 13 for facing the ring magnet 14.
A terminal 20 is mounted by means of an insulator 19 in a terminal plate 18 secured to the lower end of the casing 1.
The dynamically tuned gyro described above operates in the following manner.
When the spin motor 9 is actuated in the state of FIG. 1, the rotary shaft 5 is driven into a high-speed rotary movement, such that the gyro rotor 13 is driven into a high-speed rotary movement via hinge unit 12.
In the above state, when the gyro rotor 13 is in a tilted state, this state is sensed by the sensor coil 16, so that a required amount of control current is induced in the torquer coil 17, such that a force proportionate to the product of the control current in the torquer coil 17 and the magnetic flux in the gyro rotor 13 and ring magnet 14 is induced to effect positional control of the gyro rotor 13.
The dynamically tuned gyro described above presents the following disadvantages.
In my prior construction, the spin motor 9 adapted for causing the rotation of the rotary shaft 5 is comprised of the frame member 3, end cap 6, hysteresis ring 7 and the stator 4a arranged coaxially about the rotor shaft 5, and the casing 1 is mounted by a press fit to the radially outer wall of the frame member 3. Therefore, the gyro rotor structure is complicated and the outside diameter of the rotor is increased so that it becomes more difficult to obtain an axially elongated gyro rotor structure.
Also, the rotor shaft is of the cantilevered type, such that sufficient stability of the rotor shaft cannot be achieved.
In addition, the gyro rotor 13 itself has a U-shaped cross section, so that the radial size of the rotor cannot be reduced.